Novel 1, 2, 3-benzotriazin-4(3h)-ones



United States Patent 3,316,262 NOVEL 1,2,3-BENZOTRIAZIN-4(3H)-ONES Klaus Hasspacher and Gerhard Ohnacker, Biberach an der Riss, Germany, assignors to Boehringer Ingelheim G.m.b.H., Ingelheim am Rhine, Germany, a corporation of Germany No Drawing. Filed Aug. 4, 1964, Ser. No. 387,488 Aug. 12, 1963,

Claims priority, application Germany,

9 Claims. Ci. 260-248) This invention relates to novel 1,2,3-benzotriazin- 4(3H)-one substitution products, as well as to various methods of preparing these compounds.

More particularly, the present invention relates to 1,2,3- benzotriazin-4(3H)-ones of the formula 5 4 fi m arlq-a 7 8 1 METHOD A By reacting an anthranilic acid amide of the formula wherein R has the same meanings as in Formula I, with nitrous acid or with a compound which releases nitrous acid under the reaction conditions, such as sodium nitrite, at a temperature below 0 C., preferably in acid aqueous solution.

METHOD B By reacting an anthranilic acid lower alkyl ester of the formula s (III) wherein R has the same meanings as in Formula I. This reaction is also preferably performed in acid aqueousso lution.

METHOD o By reacting a I,2,3-benzotriazin-4(3 H)-one of the formula III-41 N with a compound of the formula R-Hal wherein R has the same meanings as in Formula I and Hal is a halogen, in the ert organic solvent, such compounds capable of neutralizing or tying up the halogen halide are alkali metals, metal hydrides.

METHOD D For the preparation of a compound of the Formula I above wherein R is haloalkyl, "by reacting a 1,2,3-benzotriazin-4(3H)-one of the formula wherein R is hydroxyalkyl, with a halogenating agent, such as a phosphorus halide or a thionyl halide, preferably in the presence of an inert organic solvent and of a Example I.-Prepamtion 0y 3-is0pr0pyl-1,2,3-benz0triazin-4(3H)-0ne by Method A A solution of 10.7 gm. of sodium nitrite in 50 cc. of Water was added dropwise to a cooled suspension of 23.2 gm. of anthranilic acid isopropylamide in 220 cc. of 2 N hydrochloric acid at a temperature between -5 and 0 C. while stirring; the sodium nitrite solution was added at a ratevsuch that the internal temperature of the reaction mixture did not rise above 0 C. After all of the sodium nitrite solution had been added, the cooling bath was re moved; a precipitate formed about 15 minutes after removal of the cooling bath. The reaction mixture was then stirred for four hours at room temperature, wherefied to be 3-isopropyl-1,2',3-benzotriazin-4(3H)-one of the formula Example 2.-Preparatin of 3-is0pr0pyl-1,2,3-benzotriazin-4(3H)-0ne by Method B Example 3. Preparation of 3-n-butyl-1,2,3-benz0triazin- 4(3H)-0ne by Method A A solution of 8 gm. of sodium nitrite in 50 cc. of water was added dropwise to a cooled suspension of 180 cc. of 2 N hydrochloric acid at 0 C. while stirring; the sodium nitrite solution was added at a rate such that the internal temperature of the reaction mixture did not rise above 0 C. After all of the sodium nitrite solution had been added the cooling bath was removed and the reaction was brought to completion by stirring the reaction mixture for four hours at room temperature. Thereafter, the reaction solution was extracted several times with ether, the extract solutions were combined and the combined ethereal solution was dried over sodium sulfate. The ether was then evaporated and the oily residue was distilled in vacuo. The fraction passing over at 181- 184 C. and 14 mm. Hg solidified upon cooling and had a melting point of 22-23 C. It was identified to be 3-nbutyl-1,2,3-benzotriazin-4(3H)-one of the formula III-Il- 0 J19 Example 4.Preparati0n of 3-benzyl-1,2,3-benz0triazin- 4(3H)-one by Method A Example 5.-Preparation of 3-benzyl-1,2,3-benz0triazin- 4(3H)-one by Method C The compound obtained in the preceding example was also obtained when 1,2,3-benZotriazin-4(3H)-one was reacted with benzyl chloride in xylene in the presence of sodium amide.

Example 6.-Prepara-ti0n of 3-(B-chl0r0ethyl)-1,2,3- benz0triazin-4(3H)-0ne by Method D 5.7 gm. of 3-(p-hydroxyethyl) 1,2,3 benzotriazin- 4(3H)-one were dissolved in 70 cc. of dry chloroform, and 3.9 gm. of thionyl chloride were added dropwise The reaction mixture was then stirred for two Thereafter it was filtered,

thereto. hours at room temperature. and the filtrate was evaporated to dryness. The solid residue was recrystallized twice from a small amount of methanol. The product had a melting point of 68-70 C. and was identified to be 3-( 8-chloroethyl)-1,2,3-benzotriazin-4(3H)-one of the formula III-CHz-CHr-Ci N Example 7.-Preparation o 3-(3'-meth0xy-n-pr0pyl)- 1,2,3-benzotriazin-4(3H)-0ne by Method A Using a procedure analogous to that described in Example 1, anthranilic acid methoxypropylamide was diazotized with an aqueous solution of sodium nitrite, yielding 3-(3'-methoxy-n-propyl) 1,2,3 benzotriazin-4(3H)- one of the formula III-lso-CrHa N The product had a melting point of 45-47 C.

Example 8.Preparati0rv of 3-n-p-r0pyl-1,2,3-benzo triazin-4(3H)-one by Method A N-Il- C aH- The product had a melting point of 61-62 C.

Example 9.Preparati0n of 3-isobutyl-1,2,3-benz0- triazin-4(3H)-one by Method A Using a procedure analogous to that described in Example 1, anthranilic acid isobutylamide was diazotized with an aqueous solution of sodium nitrite, yielding 3- isobutyl-1,2,3-benzotriazin-4(3H)-one of the formula The product had a melting point of 5354 C.

Example 10.Preparation of 3-n-hexyl-1,2,3-benz0- triazin-4(3H)-one by Method A The product had a boiling point of -136 C. at 0.05 mm. Hg.

The product had a melting point of l13-115 C.

The novel compounds according to the present invention, that is, those embraced by Formula I above, have useful pharmacodynamic properties. More particularly, they exhibit very effective antiphlogistic, antipyretic, analgesic and sedative activities in animals, coupled wth very low toxicity. Consequently, the compounds of the present invention have an unexpected significantly larged therapeutic ratio than other structual-ly related 1,2,3- benzotriazin-4(3H)-one substitution products described in the prior art.

To demonstrate the unexpected improvement in the therapeutic ratio over homologous compounds, certain lower alkyl-substituted benzotriazinones of the invention were subjected to comparative pharmacological tests for antiphlogistic activity and toxicity with adjacent lower alkyl-substituted benzotriazinones known from the prior art. More particularly, the following compounds were selected for comparison: i A. 3-methyl-1,2,3-benzotriazin-4(3H)-one lf-CH:

described in J.A.C.S., "77, 6562-6564 (1955). B. 3-ethyl-1,2,3-benzotriazin-4(3H)-one described in J.A.C.S., 77, 6562-6564 (1955).

C. 3-n-propyl-1,2,3-benzotriazin 4(3H) one prepared acording to Example 8 herein.

D. 3-isopropyl-l,2,3-benzotriazin-4(3H)-one prepared according to Example 1 herein.

These compounds were tested on groups of ten laboratory rats. An edematous condition was artificially induced in one paw of each of the rats by subcutaneous injection of a standard dose of formalin, and after the tic activity, and after the injection had taken effect the volume of water displaced by the paw was again meas- The percentage reduction of swelling was calculated from these values.

The median lethal intraperitoneal dose was determined by standard procedures for each compound in laboratory mice.

From these values the therapeutic ratio was determined for ea'ch compound, that is, the ratio of the median lethal dose (LD divided by the effective dose (ED of 50 mgm./ kg.

The following table shows the results obtained:

Reduction Thera- Compound in Swelling LD pantie Percent mgmjkg Ratio Prior Art:

These results clearly show that while the compounds according to the invention have an approximately equal or somewhat higher effectiveness as antiphlogistics as compared to the homologous prior art compounds, their toxicity is significantly smaller and their therapeutic ratio is about twice that of the lower homologs.

For therapeutic purposes the novel compounds according to the present invention are administered perorally or parenterally as active ingredients in dosage unit compositions consisting essentially of an inert, physiologically compatible carrier and one dosage unit of the active ingredient. One dosage unit of the benzotriazinones of the invention is from 50 to 250 mgm., preferably to 200 mgm. Typical dosage unit compositions are tablets, coated pills, hypodermic solutions, rectal suppositories and the like.

The following examples illustrate a few dosage unit compositions comprising a compound according to the present invention as an active ingredient. The parts are parts by weight.

Example 12 Tablets.-The tablet composition is compounded from the following ingredients:

poun the lactose, the potato starch and the talcum are thoroughly admixed with each other, the mixture is moistened with an aqueous 10% solution of the gelatin, and the moist mass is passed through a 1.5 mm.-mesh screen. The resulting granulate is dried at 40 C., is again passed through the screen, and is then uniformly admixed with the magnesium stearate. The mixture is finally pressed into 280 mgm. tablets. Each tablet contains 100 mgm. of the active ingredient.

The benzotriazinone compound, the corn starch and the lactose are thoroughly admixed with each other, the mixture is moistened with and aqueous 12.5% solution of the polyvinylpyrrolidone, and the moist mass is granulated by passing it through a 1.5 mm.-mesh screen. The granulate is dried at 45 C., passed again through the screen and is then thoroughly ad- Compounding procedure:

Example 14 Srigipositories.-The suppository composition is compounded from the following ingredients:

Parts 3-isopropyl-l,2,3-benzotriazin-4(3H)-one 200.0 Cocoa butter 1550.0

Total 1750.0

Compounding procedure: The cocoa butter is melted and at about 40 C. the finely powdered benzotriazinone compound is stirred into it. The mixture is homogenized, cooled to 35 C. and poured into cooled suppository molds, each holding 1750 mgm. of the mixture. Each suppository contains 200 mgm. of the active ingredient.

Although the above dosage unit composition examples illustrate only one of the compounds according to the present invention as an active ingredient, it should be understood that any of the other compounds embraced by Formula I may be substituted therefor in the compositions of Examples 12 tol4. Moreover, the amount of the active ingredient may be varied within the indicated limits to meet particular requirements, as may the amounts and nature of the inert ingredients.

While the present invention has been illustrated with the aid of certain specific embodiments thereof, it will be readily apparent to others skilled in the art that the invention is not limited to those embodiments and that various changes and modifications may be made without departing from the spirit of the invention or the scope of the appended claims.

We claim:

1. A compound of the formula N y wherein R is selected from the group consisting of alkyl of 3 to 6 carbon atoms, phenyhlower alkyl, halo-lower alkyl of 2 to 4 carbon atoms and lower alkoxy-lo'wer alkyl.

2. A compound of the formula wherein R is selected from the group consisting of akyl of 3 to 6 carbon atoms, benzyl, ii-phenyl-ethyl, fl-chloroethyl and methoxy-n-propyl.

. 3-isopropyl-1,2,3-benz0triazin-4-(3H)-one. 3-n-butyl-1,2,3-benzotriazin-4(3H)-one. 3-benzyl-1,2,3-benzotriazin-4(3H)-one. 3 fi-chlorethyl) -l,2,3-benzotriaZin-4(3H -one. 3-( -methoxy-n-propyl) -l ,2,3-benzotriazin-4( 3H) S-n-propyl- 1,2,3-benzotriazin-4 (3H) -0ne. 3-isobutyl-1,2,3 -benzotriazin-4 (3H -one.

References Cited by the Examiner UNITED STATES PATENTS 7/ 1958 Lorenz 260-248 OTHER REFERENCES WALTER A. MODANCE, Primary Examiner. JOHN M. FORD, Assistant Examiner.

I. Chromatog, volume 14 (1), pages 133-5 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,316, 262 April 25, 1967 Klaus Hasspacher et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 19, for "halogen" read hydrogen column 4, lines 22 to 27, the formula should appear as shown below instead of as in the patent:

column 4, lines 51 to 58, the formula should appear as shown below instead of as in the patent:

column 5, lines 8 to 14, the formula should appear as shown below instead of as in the patent:

T-ca -ca N N/ column 5, line 22, for "larged" read larger column 8, line 18, for "akyl" read alkyl Signed and sealed this 28th day of November 1967.

(SEAL) Attest:

EDWARD J. BRENNER EDWARD M.FLETCHER,JR.

Commissioner of Patents Attesting Officer 

1. A COMPOUND OF THE FORMULA 